Recommendations: Western saddle for pony???

I have a darling 12.3 ish pony that is built like a barrel, needs a U shaped tree for his english saddle. My daughter rode in my friends western saddle and loved it on her QH. So she would like a western saddle to ride our pony in.

I haven’t been in the western world in so long I don’t even know where to begin on what saddle would work.

Kids 8 and a total string bean. 50 lbs but tall. She rode in a 15" and was swimming in it. So I’m thinking a 13"?

She tacks up herself so needs to be lighter weight and hold up to getting wet. In the summer they set up sprinklers and have water gun fights on horseback.

What saddle would you recommend? Prefer less than 500.00 but don’t mind paying for something that last or has a good resell value.

I think both Abetta and Wintec make wide western saddles that are synthetic and light weight. Western seat sizes are about an inch smaller than an English seat size, so if you normally ride in a 16 inch saddle in an English saddle you’d be in a 15 inch saddle in a Western saddle.

Consider an Abetta Arabian tree: they have a rounder skirt and are meant for a shorter back (which I assume your pony has!), and are meant for a flatter (width wise) back, but the tree points aren’t as long.